package com.groupseven.backend.util;

import javax.servlet.http.HttpServletRequest;
import java.net.InetAddress;
import java.net.UnknownHostException;

public class IPUtils {


    /**
     * @program: simple_tools
     * @description: 获取IP工具类
     * @author: ChenWenLong
     * @create: 2019-10-18 11:55
     **/
    public static class IpUtils {

        public static String getIpAddr(HttpServletRequest request) {
            if (request == null) {
                return "unknown";
            }
            String ip = request.getHeader("x-forwarded-for");
            if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("Proxy-Client-IP");
            }
            if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("X-Forwarded-For");
            }
            if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("WL-Proxy-Client-IP");
            }
            if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("X-Real-IP");
            }

            if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getRemoteAddr();
            }

            return "0:0:0:0:0:0:0:1".equals(ip) ? "127.0.0.1" : ip;
        }

        public static boolean internalIp(String ip) {
            byte[] addr = textToNumericFormatV4(ip);
            return internalIp(addr) || "127.0.0.1".equals(ip);
        }

        private static boolean internalIp(byte[] addr) {
            final byte b0 = addr[0];
            final byte b1 = addr[1];
            // 10.x.x.x/8
            final byte SECTION_1 = 0x0A;
            // 172.16.x.x/12
            final byte SECTION_2 = (byte) 0xAC;
            final byte SECTION_3 = (byte) 0x10;
            final byte SECTION_4 = (byte) 0x1F;
            // 192.168.x.x/16
            final byte SECTION_5 = (byte) 0xC0;
            final byte SECTION_6 = (byte) 0xA8;
            switch (b0) {
                case SECTION_1:
                    return true;
                case SECTION_2:
                    if (b1 >= SECTION_3 && b1 <= SECTION_4) {
                        return true;
                    }
                case SECTION_5:
                    switch (b1) {
                        case SECTION_6:
                            return true;
                    }
                default:
                    return false;
            }
        }

        /**
         * 将IPv4地址转换成字节
         *
         * @param text IPv4地址
         * @return byte 字节
         */
        public static byte[] textToNumericFormatV4(String text) {
            if (text.length() == 0) {
                return null;
            }

            byte[] bytes = new byte[4];
            String[] elements = text.split("\\.", -1);
            try {
                long l;
                int i;
                switch (elements.length) {
                    case 1:
                        l = Long.parseLong(elements[0]);
                        if ((l < 0L) || (l > 4294967295L))
                            return null;
                        bytes[0] = (byte) (int) (l >> 24 & 0xFF);
                        bytes[1] = (byte) (int) ((l & 0xFFFFFF) >> 16 & 0xFF);
                        bytes[2] = (byte) (int) ((l & 0xFFFF) >> 8 & 0xFF);
                        bytes[3] = (byte) (int) (l & 0xFF);
                        break;
                    case 2:
                        l = Integer.parseInt(elements[0]);
                        if ((l < 0L) || (l > 255L))
                            return null;
                        bytes[0] = (byte) (int) (l & 0xFF);
                        l = Integer.parseInt(elements[1]);
                        if ((l < 0L) || (l > 16777215L))
                            return null;
                        bytes[1] = (byte) (int) (l >> 16 & 0xFF);
                        bytes[2] = (byte) (int) ((l & 0xFFFF) >> 8 & 0xFF);
                        bytes[3] = (byte) (int) (l & 0xFF);
                        break;
                    case 3:
                        for (i = 0; i < 2; ++i) {
                            l = Integer.parseInt(elements[i]);
                            if ((l < 0L) || (l > 255L))
                                return null;
                            bytes[i] = (byte) (int) (l & 0xFF);
                        }
                        l = Integer.parseInt(elements[2]);
                        if ((l < 0L) || (l > 65535L))
                            return null;
                        bytes[2] = (byte) (int) (l >> 8 & 0xFF);
                        bytes[3] = (byte) (int) (l & 0xFF);
                        break;
                    case 4:
                        for (i = 0; i < 4; ++i) {
                            l = Integer.parseInt(elements[i]);
                            if ((l < 0L) || (l > 255L))
                                return null;
                            bytes[i] = (byte) (int) (l & 0xFF);
                        }
                        break;
                    default:
                        return null;
                }
            } catch (NumberFormatException e) {
                return null;
            }
            return bytes;
        }

        public static String getHostIp() {
            try {
                return InetAddress.getLocalHost().getHostAddress();
            } catch (UnknownHostException e) {
            }
            return "127.0.0.1";
        }

        public static String getHostName() {
            try {
                return InetAddress.getLocalHost().getHostName();
            } catch (UnknownHostException e) {
            }
            return "未知";
        }
    }
}
